Conveying apparatus



Nov. 1, 1966 H. A. M MASTER CONVEYING APPARATUS 2 Shets-Sheet 1 OriginalFiled Dec.

INVENTOR. Ham/0 A //7- aria? 1966 H. A. MCMASTER CONVEYING APPARATUS 2Sheets-Sheet 2 Original Filed Dec. 5, 1963 United States Patent3,282,447 CONVEYING APPARATUS Harold A. McMaster, Woodville, Ohio,assignor to Permagiass, Inc., Woodville, Ohio, a corporation of OhioContinuation of application Ser. No. 328,222, Dec. 5, 1963. Thisapplication July 15, 1965, Ser. No. 478,521 22 Claims. (Cl. 214-21) Thisapplication is a continuation of application Serial Number 328,222 filedDecember 5, 1963, now abandoned.

This inventon relates to a heating apparatus and more particularly toimproved conveyor means for furnaces of the type disclosed in UnitedStates patent application Serial Number 326,713 filed November 29, 1963,in the names of Harold A. McMaster and Norman C. Nitschke and assignedto the assignee of the present invention.

In the aforesaid United States patent application there is disclosed andclaimed an improved method and appartus for manufacturing curvedtempered glass sheets on a continuous basis. In accordance with thatinvention, the glass sheets to be tempered are moved along an elongateperforated bed which extends through a heating furnace and then througha cooling blasthead, the surface of the bed within the furnace beingshaped to provide the shape desired of the glass sheets. The glasssheets are floated on the bed portion within the furnace by hot gasesemitted from the perforations therein, the gas temperature being at orabove the deformation temperature of the glass. Hence, by the time theglass sheets leave the furnace they have been heated by the hot gases todeformation temperature such that they conform to the contour of thebed. The hot glass sheets then float through the blasthead where theyare cooled by and supported by room temperature air emitted from thatportion of the bed within the blasthead.

In transporting the glass sheets across the bed, it is extremelyimportant that no contact whatever he made between the glass sheets andthe bed itself. Furthermore, the conveying means must be such as toavoid scratching, marring, or marking the glass sheets as they conveythe glass sheets across the bed. When glass is tempered, it is extremelydifficult and expensive to remove scratches, mars, or marks by polishingor in any other manner. To this end it is necessary to provide aconveying means for the glass sheet that will maintain as little contactwith the glass sheet as is possible. Since the conveying means passesthrough the heated furnace and then through the cooling blasthead,temperature changes causing expansion and contraction problems will beexperienced. Additionlly, most conveyor means such as chains, belts orthe like have a degree of vibration and slack which cause anintermittent movement of the conveyor means.

Hence, it is a principal object of the present invention to provide animproved apparatus for conveying curved sheets of glass or the likeefficiently and at relatively low cost. More specifically, it is anobject of the invention to provide apparatus of the type describedwhereby transportation of sheets or the like of exceptionally highquality can take place on a continuous high production basis atrelatively low cost with very low scrap or breakage losses. These alongwith other objects, features, and advantages of the invention willbecome more apparent from the following detailed description of apreferred embodiment thereof made with reference to the drawings inwhich:

FIGURE 1 is a perspective view, with parts broken away and partiallyschematic, of the preferred apparatus and illustrates the bedconfiguration into and through the heating furnace wherein the glasssheets are curved, and into and through blasthead wherein the curvedglass sheets are tempered.

FIGURE 2 is an enlarged elevational view with parts broken away and insection showing the conveyor means for the glass sheets in the furnaceapparatus illustrated in FIGURE 1.

FIGURE 3 is an enlarged elevational view of the conveyor meansillustrated in FIGURE 2 showing the position of the various parts.

FIGURE 4 is a cross sectional view of the conveyor means of FIGURES 2and 3 taken substantially along the line 44 of FIGURE 3 and looking inthe direction of the arrows.

FIGURE 5 is an isometric view of one link of a chain such as might beused in the conveyor means of FIG- URES 1 through 4.

Referring now to FIGURE 1, the apparatus shown comprises an elongateperforated be-d, illustrated generally by the numeral 20, which in theactual embodiment herein shown is about feet long and is composed ofthree main sections. These sections include a loading section 21, aheating and bending section 2, and a tempering section 23. The heatingand bending section 22 is within and constitutes the floor of anelongate furnace structure, illustrated generally by the numeral 24, andtempering section 23 extends through a cooling blasthead, illustratedgenerally by the numeral 25. The bed is fiat throughout section 21 andmost of section 22, and approximately two-thirds of the way throughsection 22 gradually becomes curved in a direction transverse to thelongitudinal axis of the bed. Bed section 23 within the blasthead 25 andthe portion of section 22 toward the end of the furnace adjacent theblasthead have a uniform transverse curvature the same as that desiredof the glass sheets to be manufactured. The plane of the bed is tiltedabout the longitudinal axis thereof to an angle of about 12 to thehorizontal; and hence the left longitudinal edge of the bed, as shown.at 26, is lower than the right edge 27. A chain conveyor, illustratedgenerally by the numeral 28, carrying spaced pairs of glass sheetsupport pads 29, serves to move the glass sheets over the bed 20 fromthe loading section 21 through the furnaw 24 and through out theblasthead 25. Gas emmited from perforations in the bed 20 provide a filmor cushion of gas on the bed for floatation of the glass sheetsthereover in a manner more clearly shown and described in theaforementioned United States patent application Serial Number 326,713.In essence and without attention at this time to the details describedin the aforesaid application, which details are incorporated herein byreference, the apparatus operates as follows: The glass sheets 30 to becurved and tempered are placed onto the bed at loading section 21 withthe bottom edge of each sheet resting on a pair of pads 29 secured tothe conveyor chain 28. The glass sheets are conveyed by the chain andfloat over the bed out of contact therewith by reason of the gas emittedfrom the perforations in the bed. The floating gas sheets are thusguided through the furnace 24 where they are heated to deformationtemperature by the hot gases emitted from the bed perforations and asthey reach the curved portion of section 22, the sheets sag undergravity to conform to the curvature thereof, all the while supported ongas out of contact with the bed. Hence, when the sheets reach the end ofthe furnace, they are shaped with the full curvature desired.Transportation of the floating heated curved glass sheets then continuesthrough the blasthead 25 where they are tempered by the cooling airprojected from the bed perforations in the blasthead.

It will be apparent from the foregoing that it is highly desirable toprovide a conveyor means which is not subject to changes due toexpansion and contraction caused by heat in the furnace. The conveyormeans must also pass through the furnace the length of the bed 20 and,as such, passes through the hot portion of the furnace and through thecooler blasthead. Under such conditions, the conveyor chain 23 issubject to expansion and contraction due to the heat and cold causingvariations in the length of the chain throughout the assembly. Also,conveyor chains of the type illustrated in the accompanying drawings aresubject to tolerance stackup in the manufacture and assembly thereof,the tolerances being sufiicient to cause a certain amount of slack andvibration in the chain as it travels along its circuit. Such expo si-onsand contractions, vibrations, and slack conditions all contribute to thepossiblity of improper movement of the glass sheets and theconsequential marking or marring of the edges of the sheet, as well asthe possibility of heat streaks therein as the glass sheet is movedalong the bed 22, unless such problems are eliminated.

Referring now to FIGURES 2 through 5 of the drawings, a conveyor systemis shown which avoids these problems. Suitably mounted on the apparatus,or adjacent thereto, are four sprockets 250, 251, 252 and 253. Thesesprockets are pivotally mounted in a manner to become hereinafter moreapparent and are provided with a series of teeth to receive and drivethe chain 28 extending along the length of the loading station, thefurnace 24, and the blasthead 25. Around all four of the sprockets thechain 28 is entrained. The upper sprockets 250 and 251 are disposed suchthat the upper or driving reach of the chain 28 will be disposedadjacent the edge of the bed 22 for suitable engagement with the glasssheets. The lower sprockets 252 and 253 are so located as to space thelower or driven reach of the chain 28 a suitable distance away from thedriving reach.

Chain 28 may be of any suitable construction and is shown for purposesof illustration and description as being comprised of a series of threetypes of connected links of which links 254, 255, and 256 are typical.The links are connected by suitable pivot pins 257 which permit pivotalmovement of the successive links as the chain passes over the varioussprockets. Links 256 are located at spaced points along the length ofthe chain 28 and include inwardly depending flanges 258 for purposes tobecome hereinafter more apparent. The spacing of links 256 within thechain 28 may be in any suitable pattern sufficient to accomplish thepurpose desired.

Sprockets 251 and 252 are mounted directly on the apparatus and one ofthe sprockets, such as sprocket 251, at the downstream or outlet end ofthe apparatus, is driven by suitable constant speed drive means. Anelectric motor 259, located adjacent the sprocket 251, may drivesprocket'ZSl by means of a belt or the like 260. A pulley 261, attachedor integrally formed from sprocket 251, receives the belt 269 for driveof the sprocket and the chain 28.

Sprockets 250 and 253 are rotatably mounted on a frame structure,indicated generally by the numeral 262, which is slidable longitudinallyof the chain 28. Frame structure 262 includes side members 263 slidablydisposed in bearings 264 conveniently mounted on the apparatus. Endmembers 265 and 266 separate side members 263 and complete the framestructure. Sprockets 254) and 253 are secured to either or both the sidemembers 263 and end members 265, however is convenient. Suitablyattached to end member 266 is a piston assembly 267, including acylinder 258 having a piston (not shown) reciprocable therein and apiston rod 269 extending therefrom. Cylinder 263 is suitably fixed tothe apparatus as at 27% and fluid under pressure is admitted to cylinder268 through a tube or conduit 271. Suitable fluid outlet means 283 onthe opposite side of the piston in cylinder 268 is provided, to exhaustpressure therefrom and permit movement of the piston. If desirable, theoutlet means may be restricted to restrict the flow therefrom and dampvibrations in the chain, sprockets 25% and 253 and in the framestructure 262. Thus, constant pressure is maintained at all times on theframe structure 262 to urge the sprockets 256 and 253 in a chaintightening direction. The result is to take up vibrations, slack,tolerances and thermal expansions and contractions in the chain 28.

Of course, it is to be understood that other pressure applying meanscould be used to act against frame 263, instead of piston assembly 267.For example, a suitable compression spring could be used to apply thenecessary force.

Adjacent the edge of the bed 22 and within the furnace 24 and blasthead25 is a rail 272 which may be suitably mounted to the bed supportingmeans by posts 273 and brackets, not shown. Rail 272 may be formed of aplurality of sections, closely spaced but separated a slight amount sothat expansion and contraction of the rail sections within the furnacewill not adversely affect their direction. The rails are longitudinallyaligned and are of such width as to receive the flanges 258 extendingfrom the spaced links 256 in the chain 28. The flanges 258 straddle therail 272 and thus serve to maintain the chain 28 in its properrelationship relative to the edge of the bed 22. Suitable tubularspacers 274 extending between the opposed links of the chain 28 alsoserve as bearing surfaces over the rail 272 for best operation of thechain.

The glass support pads 29 extend from chain 28 and are mounted onsuitable rods or the like 275 secured on the chain 28 in any convenientmanner and at spaced points therealong. The support pads 29 engage theedges of the glass sheets with minimal contact and are more clearlydescribed in the aforementioned United States Patent Application SerialNumber 326,713.

In order to assist the movable sprockets 250 and 253, and the framestructure 262 in maintaining the chain 28 in a taut condition, a secondcontinuous chain device, illustrated generally by the numeral 276, isprovided. Chain 275 is entrained around sprocket members 277 and 278suitably located below the chain 28 in such a manner that the upper ordriving reach of the chain 276 is in engagement with the lower or drivenreach of the chain 28. Sprocket 278 at the upstream or inlet end of theapparatus is driven by a constant speed drive means, such as motor 279connected to the sprocket 278 by means of a belt or the like 28%. Chain276 is driven at a slightly greater speed than the speed of chain 28 andthus tends to take up the slack, vibrations, and expansions andcontractions in the chain 28.

Chain 276 may be constructed in any suitable manner and is shown forpurposes of illustration and description to be formed of a series offlat plates 231, all of which are identical. One end of each of plates282 is rolled, as at 282, to form a pivot pin receiving bore therein.The opposite ends of each of the plate members 281 are pro- Vided withspaced ears 283, rolled in a similar manner and adapted to straddle thetab 282 on the next adjacent plate 281. Suitable pivot pins or the like284 extend through the ears 283 on one plate member and through the tab282 on the next adjacent plate member to form a continuous belt of suchplates. When formed in such manner, the chain 276 has a fiat outersurface which frictionally engages the links of the chain 28 along thedriven reach thereof. Such frictional engagement tends to draw the chain28 and take up the vibration, expansion and contraction, and slack thatdevelop in the chain.

The driven reach of chain 276 may be provided with anti-friction meansif desired, and for purposes of illustration and description, such meansare shown to include a plurality of ball bearings 285 suitably disposedin a groove 286 formed in a supporting structure 287 below the drivenreach of chain 2-76. Such balls 285 may be of the recirculating type ifsuch is desirable and the smooth outer surface of chain 276 ridingacross the balls 285 provides minimal contact to maintain the chain 276in as constant motion as possible.

With the chain 28 operating as above described and taking advantage ofthe movable sprockets 250 and 253 and lower chain 276, it is apparentthat the glass sheets will be moved along the support bed 22 with aslittle vibration as possible, consistent with manufacturing limits,tolerances and the like. The chain 28 is properly direoted adjacent thebed 22 by means of the rail sections 272, and thus no inward or outwardmovement relative to the bed 22 is possible. The lower chain moves slackin the upper chain toward the sprockets 250 and 253 where it is taken upby the piston and movable frame assembly 262. Further, since the lowerchain moves the bottom reach of the upper chain toward sprockets 253 and250, the upper reach of the upper chain 28 is relieved of the job ofpulling the bottom reach thereof toward said sprockets 253 and 250. Thisis an important advantage since the upper reach of chain 28, being inthe furnace, is extremely hot and subject to elongation if excessivetension is applied thereto.

It will be understood that whereas in the preferred embodiment shown apair of sprockets is used at each end of chain 28, only a singlesprocket at each end of the chain need be used. Hence, although theforegoing description and drawings illustrate a preferred embodiment ofthe invention, it is apparent that modifications and alterations theretowill occur to those having skill in the art after having had referenceto the foregoing description and drawings. However, it is not desired tolimit the invention by the foregoing but by the scope of the appendedclaims in which:

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows.

1. In a material treating apparatus having a material inlet toward oneend thereof and a material outlet toward the other end thereof, aconveyor for guiding the material through said apparatus comprising: arotatable member positioned adjacent the outlet end of said apparatus, arotatable member positioned adjacent the inlet end of said apparatus, afirst continuous loop entrained around said rotatable members with areach thereof in said apparatus, drive means for rotating one of saidrotatable members to thereby drive said first loop, means biasing one ofsaid rotatable members in a loop tightening direction to lessen theslack and vibrations in said first loop, a second continuous loopmounted adjacent the driven reach of said first loop with the drivingreach of the second loop in engagement with the driven reach of saidfirst loop, and drive means for driving said second loop at a speedslightly greater than the speed of said first loop to assist in takingup slack and vibrations in said first loop.

2. Apparatus as set forth in claim 1 and further including anti-frictionmeans disposed adjacent the driven reach of said second loop and inengagement therewith.

3. Apparatus as set forth in claim 2 wherein said antifriction meansincludes a row of ball bearings extending the length of said drivenreach of said second loop.

4. Apparatus as set forth in claim 1 wherein there are at least tworotatable members positioned adjacent the inlet end of said apparatusand wherein said biasing means comprises a frame slidably mounted onsaid apparatus and having said two rotatable members rotatably securedthereto and a hydraulic cylinder and piston assembly secured to saidapparatus and operatively connected to said frame, said assembly beingactuatable to bias said frame in a loop tightening direction.

5. Apparatus as set forth in claim 1 wherein the drive means for saidfirst loop is a constant speed motor and wherein the drive means forsaid second loop is also a constant speed motor.

6. Conveyor means for use with an apparatus and comprising: a pluralityof sprockets rotatably mounted adjacent said apparatus; a continuouschain entrained around said sprockets and adapted to move an objectalong said apparatus; drive means operatively connected to one of saidsprockets and operable to rotate said one of said sprockets and drivesaid chain; a continuous member mounted adjacent the driven reach ofsaid chain and with the driving reach thereof in engagement with thedriven reach of said chain; and means for driving said continuous membersuch that the driving reach thereof travels in the same direction as thedriven reach of said chain and at a speed slightly greater than thespeed of said chain to take up vibrations and slack in said chain andmaintain the speed of said chain constant and uninterrupted.

7. The conveyor means of claim 6 wherein said chain includes a pluralityof links rotatably secured together by pivot means.

8. The conveyor means set forth in claim 7 wherein a rail extends alongthe length of said apparatus and adjacent the driving reach of saidchain, and said chain, being provided with spaced links extending towardand engaging said rail to properly direct said driving reach of saidchain.

9. The conveyor means set forth in claim 8 and fur ther includinganti-friction means disposed adjacent the driven reach of said secondmember and in engagement therewith to maintain constant movementthereof.

10. The conveyor means set forth in claim 9 wherein said anti-frictionmeans includes a row of ball bearings extending the length of saiddriven reach of said second member and in engagement therewith.

11. The conveyor means set forth in claim 6 wherein said drive means forsaid one sprocket and said one sprocket are disposed adjacent the end ofthe driving reach of said chain, and said means for driving saidcontinuous member are disposed adjacent the end of the driving reach ofsaid continuous member.

12. The conveyor means set forth in claim 11 wherein said drive meansfor said one sprocket and said means for driving said continuous memberapply constant speed drives for said one sprocket and said continuousmember respectively.

13. The conveyor means set fonth in claim 6 and further including aframe structure rotatably mounting a pair of said sprockets at the endof said chain remote from said drive means for said chain, said framestructure being slidably mounted on said apparatus, and means tending tomove said frame structure and said pair of sprockets in a chaintightening direction.

14. The conveyor means set forth in claim 13 wherein said means tendingto move said frame structure includes a hydraulic cylinder secured tosaid apparatus and having fluid inlet and outlet means therein, saidcylinder having a piston reciprocable therein and operably connected tosaid frame stucture for moving said structure and said pair of sprocketsin response to fluid pressure in said cylinder.

15. The conveyor means set forth in claim 14 wherein said fluid outletmeans is restricted to restrict fluid flow therefrom and damp vibrationsin said chain and said frame structure and said pair of sprockets.

16. In an elongate materials treating apparatus having a material inletat one end thereof and a material outlet at the other end thereof, aconveyor for guiding said material through at least a portion of saidapparatus comprising a closed loop extending longitudinally of saidapparatus between said inlet and said outlet, a driving rotary member inengagement with said loop and positioned toward said outlet, an idlerrotary member in engagement with said loop and positioned toward saidinlet, means biasing said idler rotary member in a direction away fromsaid driving rotary member to thereby reduce the amount of slack in saidloop, a second closed loop extending parallel to said first mentionedloop with a portion thereof in engagement with said first mentionedloop, a driving rotary member in engagement with said second mentionedloop positioned toward the inlet end of said apparatus and idler rotarymember in engagement with said second mentioned loop positioned towardthe outlet end of said apparatus, said loops being driven in oppositerotary directions, said second mentioned loop being driven slightlyfaster than said first mentioned loop whereby said second mentioned loopurges any slack in that portion of the first mentioned loop with whichit is in engagement toward the idler rotary member for said firstmentioned loop and attenuates vibrations in said first mentioned loop.

17. Apparatus as set forth'in claim 16 wherein each of said drivingrotary members has its own constant speed drive means.

18. Apparatus for treating articles comprising; a furnace, a conveyorfor moving articlesthrough said furnace, said conveyor including acontinuous loop having a driving reach and a driven reach, said drivingreach extending through said furnace, a first drive means for movingsaid loop, a second drive means for driving said loop, said second drivemeans engage-able with said loop for urging said loop to move at afaster speed than said loop is moved by said first drive means, andmeans for allowing slippage between said second drive means and saidloop thereby to inhibit slack and vibrations in said loop so that thespeed of said driving reach is substantially constant.

19. Apparatus for treating articles comprising; a furnace, a conveyorfor moving the articles through said furnace at a substantially constantspeed, said conveyor including a continuous loop having a driving reachand a driven reach, said driving reach extending through said furnace,said conveyor being entrained about a first drive means for driving saidloop and an idler means for biasing said loop in a loop tensionincreasing direction, a second drive means engagable with said drivenreach of said loop as said loop moves from said drive means to saididler means for urging said driven reach of said loop to move at afaster speed than said driving reach of said loop, and means forallowing slippage between said second drive means and said driven reachof said loop thereby to inhibit slack and vibrations in said loop sothat the speed of said driving reach of said loop is substantiallyconstant.

28. Apparatus for conveying an article comprising a continuous memberforming an elongated loop entrained around and having two reachesextending between spaced rotatable members, means adjacent one end ofsaid elongated loop for driving said loop, means adjacent the other endof said elongated loop for tensioning said loop, said loop having meansfor contacting the article and moving it with one of the reaches of saidloop, and means for urging the other reach of said loop in the directionof said tensioning means.

21. Apparatus for conveying an article comprising a continuous memberforming an elongated loop entrained around and having two reachesextending between spaced rotatable members, drive means associated withone of said rotatable members at one end of said elongated loop fordriving said loop, tensioning means at the other end of said elongatedloop associated With the other of said rotatable members for tensioningsaid loop, said loop having means for contacting the article and movingit with one of the reaches of said loop, and means urging the otherreach of said loop in the direction of said tensioning means.

22. Apparatus for conveying spaced sheets while said sheets aresupported on gas comprising a continuous member forming an elongatedloop entrained around and having two reaches extending between spacedrotatable members, means adjacent one end of said elongated loop fordriving said loop, spaced supports extending laterally from said loopfor frictionally engaging said sheets laterally of one reach of saidloop whereby said sheets are caused to move with said loop laterally ofsaid one reach, means adjacent the other end of said elongated loop fortensioning said loop and means urging the other reach of said loop inthe the direction of said tensioning means.

References Cited by the Examiner UNITED STATES PATENTS 2,103,680 12/1937Klaucke 198-189 2,295,401 9/1942 Hansen 214-21 2,650,695 9/ 1953 Robins198-208 2,797,075 6/1957 Wilbur 198-208 X 2,868,356 1/1959 Haaf 198-2032,925,165 2/1960 Rake 198-198 3,039,597 6/1962 Merchant 198-2083,086,824 4/1963 Barkley 308-6 FOREIGN PATENTS 622,748 3/ 1963 Belgium.

GERALD M. FORLENZA, Primary Examiner.

R. G. SHERIDAN, Assistant Examiner.

20. APPARATUS FOR CONVEYING AN ARTICLE COMPRISING A CONTINUOUS MEMBERFORMING AN ELONGATED LOOP ENTRAINED AROUND AND HAVING TWO REACHESEXTENDING BETWEEN SPACED ROTATABLE MEMBERS, MEANS ADJACENT ONE END OFSAID ELONGATED LOOP FOR DRIVING SAID LOOP, MEANS ADJACENT THE OTHER ENDOF SAID ELONGATED LOOP FOR TENSIONING SAID LOOP, SAID LOOP HAVING MEANSFOR CONTACTING THE ARTICLE AND MOVING IT WITH ONE OF THE REACHES OF SAIDLOOP, AND MEANS FOR URGING THE OTHER REACH OF SAID LOOP IN THE DIRECTIONOF SAID TENSIONING MEANS.